Distance-measuring instrument.



H. JACOB.

DISTANCE MEASURING INSTRUMENT.

APPLICATION FILED MAR.24. I913.

Patented Nov. 16, 1915.

2 SHEETSSHEET 1.

H. JACOB.

DISTANCE MEASURING INSTRUMENT.

APPLICATION FILED MAR. 24. 1913.

1,180.,6 1 v Patented Nov. 16, 1915.

2 SHEETSSHEET 2.

' HEINRICH moon, or srEGLIrz, NEAR BERLIN, GERMANY, ASSIGNOR To THE FIRM.

or OPTISCHE ANSTALT c. P. GOERZ AKTIENGESELLSGHAFT, F FRIEDENAU, NEAR BERLIN, GERMANY.

DISTANCE-MEASURING INSTRUMENT.

Specificationof Letters Patent. v Patented Nay. 11% 1915 Application filed March 24, 1913. Serial No. 756,423.

To all whom it may concern,

Be it lmown that I, HEINRICH JACOB, a

citizen of the German Empire, and resident of Steglitz, near Berlin,-Germany, have invented certain new and useful Improvements in Distance-Measuring Instruments, of which the following is a specification;

This invention consists in an improvement in, or modification of a distance measuring instrument of the coincident image'type described in the specification of United States Patent No. 1,038,831, The base line telemeter described and illustrated in the said patent is provided with an ocular prism device having reflecting surfaces arranged partially on the one and partially on the other side "of a straight edge transversing the field of view of the instrument. With this device, either the bases or the tops of the two images may be made to coincide, and for the purpose of translation from one image position to the other, it is necessary to turn the whole instrument, which is not only inconvenient but is also liable to cause mistakes. Moreover, the instrument has the disadvantage that the effective field of view is smallerv than the total field of view of the instrument, since only that part of the field can be used which'lies on one side of the dividing line. I According to my present invention I obviate these defects by making the ocular prism body movable so that its reflective surfaces disposedon opposite sides ofthegdividing line can-be dlsplaced in their own planes. This enables the whole field of view of the instrument to be utilized for all kinds of ob servation, and renders turning of the instrument unnecessary.

The accompanymg drawlngs show several forms of construction embodying this inven .of reflector surfaces provided in the system in the plane intersecting the ocular image plane. Figs. 3 and 4 represent fields of view of the instrument when it is trained on a balloon, these views showing the two .alternative positions of the images. Fig. 5 shows another arrangement of the reflect ve surface in the plane intersecting the image plane of the ocular, wher'eby,in a similar manner to Fig. 2, the borders of the field of view being indicated by dotted cir neously displacing the dividing line in the field of view.

In the optical'system shown in Fig. l, the two objectives of the instrument are designated by 1, 2; 3 being the ocular. Penta prisms 4 or 5 are mounted in front of-the objectives in the known manner. 6 designates a movable wedge like prism and pointer, by adjustment of which the images of distance objects appearing on opposite sides of the dividing line in the field of view are brought into coincidence with each other. the position of the pointer 6 indicating the distance of the objects whereof the image's coincide. 7 and 8 are prisms which deflect the rays from the objectives 1, 2 toward the ocular 3. ais a fixed prism which receives the rays passing from the objective 2 through the prism 8. 1O designates a reflective surface of this prism, by which the rays entering theprism are reflected to a prism body 11 cementedto a prism body 12. The prismbody 12 is fixed to a movable slide 13, which is guided in a fixed carrier ll. At the cemented surface of the compound prism 11, 12 there are two mirrors 15, 16, the edges ofnwhich form the dividing line 17 in the image plane of the ocular 3. w The cement surface between the prismsll, 12, which are provided with the reflective surfaces or mirrors 15, 16, intersects the image plane of the ocular at the line 17. The path of the axial rays is shown in Fig- 1. It will be seen that with the compound prisms 11, 12 ad justed so that the mirror 15 is in use. the

the image which appears above the dividing line 17 shows the observed object inan up-' right position, whereas the image below the dividing line is inverted, as shownin Fig. 3. If however. the compound prism 11, 12 is moved with its carrier 13in the guide 1-1 in such manner that the mirror 16 comes into use, theimages of the object observed appear as shown in Fig. -l.

The arrangement of the reflective surfaces in the plane intersectingthe image plane two parts cemented together.

mented surface are two mirror surfaces '21,

of the ocular may be modified in various ways. For instance, the reflector surfaces may be-narrow strips, as shown in Fig. 5, these strips being either contiguous or separated from each other, If-as is preferable, theplace of coincidence" of the images in the field of view is always at the same height, the-edges of the reflector surfaces which form the dividing line must lie on a straight line. as is the case with the arrangements according to Figs. 2 and 5.

The arrangement describedmayb'e" used with ocular prismsof any "shape.

The ocular prism system shown in Figs.

6 and T, frr a distance measuring instrument having an angular line of vision, is the equivalent of the prisms 7, S, 9, 11-, 1:2 in Fig. 1, and comprises two prisms 18,19 for deflecting the rays toward the ocular, and\a movable prism body '20 which comprises Atthe ce- 2'2, the edges '23 of which form the dividing line in the image field. By displacing the prism body 20 with relation tothe prisms 18. 19 either the mirror 21 or the mirror :22 can be broughtinto use.v Thepath of the ravs'is shown in Fig. 6. The'arrangement shown in Fig. 8 is substantially similar to that shown" in Fig.7, with the exception that 4 the prism system which has the mirror surfaces 21, '22 at the cementedfsurface is divided into two parts, at 2- so that the parttions. is placed so that the upright image appears. in the larger field section. the inverted image appearing in the smaller field section. This arrangement is advantageous in that itprovides a large field for orientation.

The carrier of the reflective surfaces in the ocular prism body which are designated 15. 16 as in Figs. 1 and '2, is provided with a rack 25 engaged with a toothed ring or' flange '26 on the ocular tube 27. The holder '25 of the ocular is eccentrically fixed to the ocular tube 27. By turning the ocular tube.

27 the carrier of the reflecting surfaces 15 and 16 is moved and the position of the holder 28 is simultaneously shifted with respect to the border line-17 of'the reflective 16, as shown in Figs. 9 and 11.

surfaces 15, This displacement of the ocular holder 28 is [equivalent to a displacement of the dividing line in the image field, so that'the field of view "either appears as shown in Fig. 10 or as shown inv Fig. 12', according to whether.

the reflecting surface 15 or the surface 16 is used.

What I claim is: v

1. In a base line telemeter an ocular prism device provided with an element-carrying reflecting surfaces, means for shifting said element so as to displace a reflecting surface provided"t-hereon,.in its own plane.

2. In abase line telemeter an ocular prism device having a. movable element provijled withreflect-ing layers in a plane surface said reflecting layers having straight limiting edges adapted to form image dividing lines within the field of view, the reflecting layers arranged partially on the one and partially on the other side of their image dividing lines forming limiting edges, and" the movable elementcarrying reflecting layers adapted to be displaced so as to bring at will a reflecting layer positioned on one side of an image dividing line into operative position or a reflecting layer positioned on-the other side.

3. In a baseline telemeter an ocular, and an ocular prism device having a movable ele;

ment carrying plane reflecting surfaces with straight limiting edges, means for connecting said ocular and said movable element, the reflecting surfaces being so arranged on said movable element that on displacing same, either one reflecting surface or. the other can be broughtin front of the ocular, the straightlimiting edges of the reflecting surfaces forming insuch operative position image dividing lines. in the field of view, the surfaces being positioned on opposite sides of the limiting edges.

4. In a base line telemeter an ocular, a rotatable carrier for same having its axis of rotation arranged parallelly but eccentrically to the optical axis of the ocular, an ocular prismde'vice hav ng an element carrying reflecting surfaces with straight limiting ed es, the edges adapted to form image dividing lines within the field of view and the reflecting surfaces positioned on opposite sides of the limiting edges, the carrier of the reflecting surfaces being movable in the direction of the limiting edges of the reflecting surfaces and so interconnected with the ro-' tatable ocular carrier that on rotating the latter the reflecting surface carrier is'shifted and the ocular is displaced transi'ersely' to the direction of shifting the ocular prism amet;

element in such a way that in different opspecification in the presence of two subscriberative positions of the prism element the ing Witnesses. image field sections of greater area are posi- HEINRICH JACOB. tioned onopposite sides of the'image divid- Witnesses: 5 ing line Within the field ofview. HENRY HASPER,

In testimony whereof I have signed this WOLDEMAR HAUPT. 

